The present invention relates to improvements in radio telephone systems.
Several automatic and semi-automatic mobile radio telephone systems have been in operation in many parts of the world for the past few years. The two systems presently most widely used are the Improved Mobile Telephone System (IMTS) described in U.S. Pat. No. 3,351,714, and the Mobile Automatic Telephone System, described by Jochen Wernter in "Mobile Telephone System Calls Long Distance Distances Automatically", Tekade Felten & Guilleume Fernmeldeenlagen GmbH-Nurnberg (Phillips Group), March 1975. These and other systems in present use provide radio telephone service of reasonable caliber to mobile subscribers, in keeping with the requirements and technology available at the time of their inception. The present and projected future demands for more comprehensive subscriber facilities and operating improvements, however, have outstripped the capabilities of those prior systems.